Plant Biotechnology 8 Flashcards
What do agronomic traits include?
Yield
Herbicide tolerance
Disease and pest resistance
What do quality traits include?
Processing
Shelf life
Nutritional quality
Name 3 novel products that can be grown in plants
Oils
Proteins
Polymers ie. plastics
Describe roundup ready
Broad spectrum herbicide made by Monsanto
Glyphosate
Acts by inhibiting a chromoplast enzyme
What are advantages of HT (herbicide tolerant) crops?
Enhanced crop productivity
Encourages ’no-till’ agriculture – reducing soil erosion and lowering fuel costs and greenhouse gas emissions
What are disadvantages of HT (herbicide tolerant) crops?
Increased use of Roundup
Possible reduction in biodiversity
What bacteria is most commonly used for insect resistance?
Bacillus thuringiensis (Bt)
How does Bacillus thuringiensis (Bt) work?
Its spores contain a crystalline protein that kills insects
- Larva consumes toxin
- Crystals solubilized and toxin activated by proteolytic cleavage in mid-gut
- Toxin binds to specific receptors
- Binding triggers cell death in mid-gut lining
- Septicaemia follows and larva dies
Which gene encode the Bt toxins?
Cry genes
What are the advantages of using Bt crops?
reduced financial cost due to less pesticide use
Reduced environmental impact
Improved health of farmers
Improved food quality
What are the disadvantages of using Bt crops?
Selection pressure for resistant pests
Possible effect on non target insects
What is golden rice?
Provitamin A-enriched rice variety
Where do humans normal get vitamin A from?
Provitamin A from plants
From animal products containing vitamin A
Describe what happens when someone has a vitamin A deficiency
Night-blindness
Dry eyes (xerophthalmia)
Increased susceptibility
Developing countries
What is a main cause of VAD?
Low vitamin A content of the rice grain as it is staple diet all over the world
Why does rice have little vitamin A?
Due to little of β-carotene
There are 4 missing enzyme catalysed steps
How was rice made that is rich in β-carotene (golden rice)?
Introduced two daffodil genes and an Erwinia gene under the control of endosperm-specific promoters into rice
Golden rice 2 can provide how much of a childs RDA of Vitamin A?
50%
What is an advantage of golden rice?
saves people from going blind
What is a disadvantage of golden rice?
Reinforces dependancy on rice diet
What are aphids?
Major agricultural pests, damaging crops and carrying important plant viruses
What is the aphid alarm pheromone?
A volatile, non-toxic chemical produced by aphids in response to attack.
What is an edible vaccine?
Vaccines where the antigen is produced in a transgenic plant and can be administered orally.
What is an advent of edible vaccine?
Production is efficient and easily scaled up
Don’t require refrigeration
How are edible vaccines developed for the measles virus?
Select an antigen surface exposed protein targeted during the immune response
Isolate the MV-H gene
Express the gene in an edible transgenic plant
Test effectiveness by feeding the lettuce to mice
Assay for the presence of anti-MV-H antibodies in mice
